Aqueous Zn-ion batteries(AZIBs)have attracted increasing attention in next-generation energy storage systems due to their high safety and economic.Unfortunately,the side reactions,dendrites and hydrogen evolution effe...Aqueous Zn-ion batteries(AZIBs)have attracted increasing attention in next-generation energy storage systems due to their high safety and economic.Unfortunately,the side reactions,dendrites and hydrogen evolution effects at the zinc anode interface in aqueous electrolytes seriously hinder the application of aqueous zinc-ion batteries.Here,we report a critical solvation strategy to achieve reversible zinc electrochemistry by introducing a small polar molecule acetonitrile to form a“catcher”to arrest active molecules(bound water molecules).The stable solvation structure of[Zn(H_(2)O)_(6)]^(2+)is capable of maintaining and completely inhibiting free water molecules.When[Zn(H_(2)O)_(6)]^(2+)is partially desolvated in the Helmholtz outer layer,the separated active molecules will be arrested by the“catcher”formed by the strong hydrogen bond N-H bond,ensuring the stable desolvation of Zn^(2+).The Zn||Zn symmetric battery can stably cycle for 2250 h at 1 mAh cm^(-2),Zn||V_(6)O_(13) full battery achieved a capacity retention rate of 99.2%after 10,000 cycles at 10 A g^(-1).This paper proposes a novel critical solvation strategy that paves the route for the construction of high-performance AZIBs.展开更多
The influence of curing temperature on the strength development of cement-stabilized mud has been well documented in terms of strength-increase rate and ultimate strength.However,the strength development model is not ...The influence of curing temperature on the strength development of cement-stabilized mud has been well documented in terms of strength-increase rate and ultimate strength.However,the strength development model is not mature for the extremely early stages.In addition,there is a lack of studies on quality control methods based on early-stage strength development.This paper presents a strength model for cement-stabilized mud to address these gaps,considering various curing temperatures and early-stage behaviors.In this study,a series of laboratory experiments was conducted on two types of muds treated with Portland blast furnace cement and ordinary Portland cement under four different temperatures.The results indicate that elevated temperatures expedite strength development and lead to higher long-term strength.The proposed model,which combines a three-step conversion process and a hyperbolic model at the reference temperature,enables accurate estimate of the strength development for cement-treated mud with any proportions cured under various temperatures.With this model,a practical early quality control method is introduced for applying cement-stabilized mud in field projects.The back-analysis parameters obtained from a 36-h investigation at temperature of 60C demonstrated a sufficient accuracy in predicting strength levels in practical applications.展开更多
More than 30 species of benthic Prorocentrum have been identified,some of which produce okadaic acid(OA)and its derivatives,dinophysistoxins(DTXs),which cause diarrhetic shellfish poisoning(DSP).Increasing numbers of ...More than 30 species of benthic Prorocentrum have been identified,some of which produce okadaic acid(OA)and its derivatives,dinophysistoxins(DTXs),which cause diarrhetic shellfish poisoning(DSP).Increasing numbers of benthic Prorocentrum species have been reported in tropical and subtropical waters of China.In contrast,only a few benthic Prorocentrum species have been reported in temperate waters.In this study,morphological descriptions obtained using light microscopy,scanning electron microscopy and molecular characterization of one Prorocentrum clipeus strain isolated from the Yellow Sea are presented.Prorocentrum clipeus cells were nearly circular in shape,with a collar,ridge,and one protrusion.The periflagellar area was wide U-shaped,with two curved projections on platelet 1a.Nine periflagellar platelets of different sizes were observed.The morphology closely fits that of the species isolated from other locations.Phylogenetic analysis based on the molecular sequences of the small subunit(SSU)rDNA,internal transcribed spacer(ITS),and large subunit(LSU)rDNA was performed.A comprehensive metabolomic analysis incorporating target,suspect and non-target screenings was first applied to investigate the intracellular and extracellular metabolite profiles of the current isolate of P.clipeus.According to the results of the target and suspect screenings,179 metabolites or toxins produced by DSP-related algal species,including OA,dinophysistoxin-1(DTX1),dinophysistoxin-2(DTX2)and pectenotoxin-2(PTX2),were not detected.Non-target screening involving feature-based molecular networking(FBMN)provided a global view of major metabolites produced by the P.clipeus DF128 strain and revealed 23 clusters belonging to at least 13 compound classes,with organometallic compounds,lipids and lipid-like molecules,phenylpropanoids and polyketides,and benzenoids as major types.To date,this is the first record of the characterization of P.clipeus in samples from Chinese waters.Our results support the wide distribution of epibenthic Prorocentrum species.展开更多
Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chl...Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).展开更多
Early-onset mental disorders are associated with disrupted neurodevelopmental processes during adolescence.The methylazoxymethanol acetate(MAM)animal model,in which disruption in neurodevelopmental processes is induce...Early-onset mental disorders are associated with disrupted neurodevelopmental processes during adolescence.The methylazoxymethanol acetate(MAM)animal model,in which disruption in neurodevelopmental processes is induced,mimics the abnormal neurodevelopment associated with early-onset mental disorders from an etiological perspective.We conducted longitudinal structural magnetic resonance imaging(MRI)scans during childhood,adolescence,and adulthood in MAM rats to identify specific brain regions and critical windows for intervention.Then,the effect of repetitive transcranial magnetic stimulation(rTMS)intervention on the target brain region during the critical window was investigated.In addition,the efficacy of this intervention paradigm was tested in a group of adolescent patients with early-onset mental disorders(diagnosed with major depressive disorder or bipolar disorder)to evaluate its clinical translational potential.The results demonstrated that,compared to the control group,the MAM rats exhibited significantly lower striatal volume from childhood to adulthood(all P<0.001).In contrast,the volume of the hippocampus did not show significant differences during childhood(P>0.05)but was significantly lower than the control group from adolescence to adulthood(both P<0.001).Subsequently,rTMS was applied to the occipital cortex,which is anatomically connected to the hippocampus,in the MAM models during adolescence.The MAM-rTMS group showed a significant increase in hippocampal volume compared to the MAM-sham group(P<0.01),while the volume of the striatum remained unchanged(P>0.05).In the clinical trial,adolescents with early-onset mental disorders showed a significant increase in hippocampal volume after rTMS treatment compared to baseline(P<0.01),and these volumetric changes were associated with improvement in depressive symptoms(r=−0.524,P=0.018).These findings highlight the potential of targeting aberrant hippocampal development during adolescence as a viable intervention for earlyonset mental disorders with neurodevelopmental etiology as well as the promise of rTMS as a therapeutic approach for mitigating aberrant neurodevelopmental processes and alleviating clinical symptoms.展开更多
水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵...水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵根离子插层机制所形成的N–H···O强键合作用来稳定Mo–MnO_(2)的2×2隧道结构,并且有效抑制了Mn^(3+)溶解,在质子插入/脱出过程中不会引起晶格的畸变,进一步提高了其循环稳定性.获得的Mo–MnO_(2)正极在100 mA g^(−1)时表现出265.2 mA h g^(−1)的高比容量和364.3 W h kg^(−1)的能量密度.在2.0 A g^(−1)下1000次循环后,容量保持率达95.2%.这项工作有助于深入了解非金属阳离子在电极主体材料间的键合作用,为设计具有高能量密度和长期循环能力的水系锌离子电池提供了新思路.展开更多
In this paper,we develop an exhaustive numerical simulator for the dynamic visualization and behavior prediction of the tether-net system during the whole space debris capture phases,including spread,contact,and close...In this paper,we develop an exhaustive numerical simulator for the dynamic visualization and behavior prediction of the tether-net system during the whole space debris capture phases,including spread,contact,and close.First of all,to perform its geometrically nonlinear deformation,discrete different geometry theory is applied to model the mechanical response of a flexible net.Based on the discretization of the whole structure into multiple vertexes and lines,the internal force and associated Hession are derived in a closed form to solve a series of nonlinear dynamic equations of motion.The spread and deployment of a packaged net can be realized using this well-established net solver.Next,a multidimensional incremental potential formulation is selected to achieve the intersection-free boundary nonlinear contact and collision between the deformable net and rigid debris.Finally,for the closing mechanism analysis,a log-like barrier functional is derived to achieve the nondeviation condition between the ring–rod linkage system.The C2 continuous log barrier functionals constructed for both the contact model and the linkage system are smooth and differentiable,and,therefore,the nonlinear net capture dynamic system can be efficiently solved through a fully implicit time integrator.Overall,as a demonstration,the whole capture process of a defunct satellite using a hexagon net is simulated through our well-established numerical framework.We believe that our comprehensive numerical methods could provide new insight into the optimal design of active debris removal systems and promote further development of the online control of tether tugging systems.展开更多
A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrotherm...A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrothermal and microwave hydrothermal method.The morphological studies revealed that the ZnFe-LDO/Co_(3)O_(4) composites exhibited a flower-like structure comprising Co_(3)O_(4) nanowires and ZnFe-LDO nanosheets.Further,when the mass ratio of Co(NO_(3))_(2)·6H_(2)O/LDH was 1:1.8 and the calcination temperature was 550℃,the ZnFe-LDO/Co_(3)O_(4) composite exhibited 93.3%degradation efficiency for methylene blue(MB)at the applied voltage of 1.0 V under visible light after 3 h.Furthermore,the Mott-Schottky model experiments showed that the formation of a p-n heterojunction between ZnFe-LDO and Co_(3)O_(4) could effectively inhibit the recombination of electrons and holes in the photoelectrocatalytic process.Meanwhile,free radical scavenging experiments showed that the active radicals of⋅OH played an important role in the degradation of MB.Therefore,the photoelectrocatalytic effect of ZnFe-LDO/Co_(3)O_(4) provides a simple and effective strategy for the removal of organic pollutants.展开更多
A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete(PC)box-girder bridge.The change of hydration heat temperature consists of ...A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete(PC)box-girder bridge.The change of hydration heat temperature consists of four periods:temperature rising period,constant temperature period,rapid temperature fall period and stow temperature fall period.The peak value of hydration heat temperature increases with the increasing casting temperature of concrete;the relation between them is approximately linear.According to field tests,the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder.Furthermore,the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring.Such results show that the prevailing Chinese Code(2004)is insufficient since it does not take into account the temperature gradient of the bottom slab.Finally,some preventive measures against temperature cracks were proposed based on related studies.The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.展开更多
Based on high specific surface area,high porosity of metal-organic frameworks(MOFs)and excellent vis-ible light response of CdS,the CdS/Cd-MOF nanocomposites were constructed by in-situ sulfurization to form CdS using...Based on high specific surface area,high porosity of metal-organic frameworks(MOFs)and excellent vis-ible light response of CdS,the CdS/Cd-MOF nanocomposites were constructed by in-situ sulfurization to form CdS using Cd-MOF as precursor and the CdS loading was controlled by the dose of thioac-etamide.Under the irradiation of simulated sunlight,the degradation rate of methylene blue(MB)by 10mg MOF/CdS-6(mass ratio of MOF to thioacetamide is 6:1)was 91.9%in 100min,which was higher than that of pure Cd-MOF(62.3%)and pure CdS(67.5%).This is attributed to the larger specific surface area of the composite catalysts,which provides more active sites.Meanwhile,the loading of CdS obvi-ously broadens the light response range of Cd-MOF and improves the utilization of visible light.The Mott-Schottky model experiment shows that the formed type-Ⅱheterojunction between Cd-MOF and CdS can effectively inhibit the recombination of photogenerated electrons and holes.Meanwhile,the photocurrent intensity of MOF/CdS-6 is 8 times and 2.5 times of that of pure Cd-MOF and CdS.In addi-tion,MOF/CdS-6 showed good photocatalytic performance after five cycles,showing excellent stability and reusability.展开更多
This paper deals with the floating resistance of super large caisson by numerical simulation,and the influence of air resistance on the caisson,which is often ignored by previous researchers,is considered.The floating...This paper deals with the floating resistance of super large caisson by numerical simulation,and the influence of air resistance on the caisson,which is often ignored by previous researchers,is considered.The floating caisson of Taizhou Highway Bridge’s middle tower pier is investigated,and the software package FLUENT is used to simulate the floating process of largescale rounded rectangular steel caisson.This simulation adopts the volume of fluid(VOF)model with water-air two-phase flow,which can take both the hydraulic resistance and air resistance into account.Subsequently,the analyses on hydraulic resistance and air resistance under different working conditions,such as different flow velocities and different draughts of water are performed,and the results are compared with those calculated by related empirical formula.The comparison shows that the air resistance takes up notable portion in the total resistance on the floating caisson,and the effect of air resistance on the safety of caisson should be paid sufficient attention to rather than be ignored.展开更多
Concrete box culverts are widely used in expressways in mountain areas.Many problems frequently take place due to improperly estimated vertical earth pressures on culverts.The prevailing Chinese General Code for Desig...Concrete box culverts are widely used in expressways in mountain areas.Many problems frequently take place due to improperly estimated vertical earth pressures on culverts.The prevailing Chinese General Code for Design of Highway Bridges and Culverts(CGCDHBC)stipulates the computation of the design load on culverts primarily based on the linear earth pressure theory,which cannot accurately describe the variation of the vertical load on culverts in trenches.In this paper,a full-scale experiment and numerical simulation were conducted to evaluate the variation of vertical earth pressures on culvert and soil arching in backfill.The variations of foundation pressure and settlement were also analyzed.The result revealed that the soil arch forms when the backfill on the culvert reaches a certain height.The soil arching effect reduces the stress concentration on the crown of the culvert but it is unstable.The vertical earth pressure on top of the culvert is significantly different from that recommended by the CGCDHBC.展开更多
Background:The coronavirus disease 2019(COVID-19)is a highly infectious respiratory disease.There is no recommended antiviral treatment approved for COVID-19 in Sierra Leone,and supportive care and protection of vital...Background:The coronavirus disease 2019(COVID-19)is a highly infectious respiratory disease.There is no recommended antiviral treatment approved for COVID-19 in Sierra Leone,and supportive care and protection of vital organ function are performed for the patients.This study summarized the clinical characteristics,drug treatments,and risk factors for the severity and prognosis of COVID-19 in Sierra Leone to provide evidence for the treatment of COVID-19.Methods:Data of 180 adult COVID-19 patients from the 34th Military Hospital in Freetown Sierra Leone between March 31,2020 and August 11,2020 were retrospectively collected.Patients with severe and critically ill are classified in the severe group,while patients that presented asymptomatic,mild,and moderate disease were grouped in the non-severe group.The clinical and laboratory information was retrospectively collected to assess the risk factors and treatment strategies for severe COVID-19.Demographic information,travel history,clinical symptoms and signs,laboratory detection results,chest examination findings,therapeutics,and clinical outcomes were collected from each case file.Multivariate logistic analysis was adopted to identify the risk factors for deaths.Additionally,the clinical efficacy of dexamethasone treatment was investigated.Results:Seventy-six(42.22%)cases were confirmed with severe COVID-19,while 104 patients(57.78%)were divided into the non-severe group.Fever(56.67%,102/180)and cough(50.00%,90/180)were the common symptoms of COVID-19.The death rate was 18.89%(34/180),and severe pneumonia(44.12%,15/34)and septic shock(23.53%,8/34)represented the leading reasons for deaths.The older age population,a combination of hypertension and diabetes,the presence of pneumonia,and high levels of inflammatory markers were significantly associated with severity of COVID-19 development(P<0.05 for all).Altered level of consciousness[odds ratio(OR)=56.574,95%confidence interval(CI)5.645–566.940,P=0.001],high levels of neutrophils(OR=1.341,95%CI 1.109–1.621,P=0.002)and C-reactive protein(CRP)(OR=1.014,95%CI 1.003–1.025,P=0.016)might be indicators for COVID-19 deaths.Dexamethasone treatment could reduce mortality[30.36%(17/56)vs.50.00%(10/20)]among severe COVID-19 cases,but the results were not statistically significant(P>0.05).Conclusions:The development and prognosis of COVID-19 may be significantly correlated with consciousness status,and the levels of neutrophils and CRP.展开更多
The probability analysis of ground deformation is becoming a trend to estimate and control the risk brought by shield tunnelling.The gap parameter is regarded as an effective tool to estimate the ground loss of tunnel...The probability analysis of ground deformation is becoming a trend to estimate and control the risk brought by shield tunnelling.The gap parameter is regarded as an effective tool to estimate the ground loss of tunnelling in soft soil.More specifically,x,which is a gap parameter component defined as the over(or insufficient)excavation due to the change in the posture of the shield machine,may contribute more to the uncertainty of the ground loss.However,the existing uncertainty characterization methods for x have several limitations and cannot explain the uncertain correlations between the relevant parameters.Along these lines,to better characterize the uncertainty of x,the multivariate probability distribution was developed in this work and a dynamic prediction was proposed for it.To attain this goal,1523 rings of the field data coming from the shield tunnel between Longqing Road and Baiyun Road in Kunming Metro Line 5 were utilized and 44 parameters including the construction,stratigraphic,and posture parameters were collected to form the database.According to the variance filter method,the mutual information method,and the value of the correlation coefficients,the original 44 parameters were reduced to 10 main parameters,which were unit weight,the stoke of the jacks(A,B,C,and D groups),the pressure of the pushing jacks(A,C groups),the chamber pressure,the rotation speed,and the total force.The multivariate probability distribution was constructed based on the Johnson system of distributions.Moreover,the distribution was satisfactorily verified in explaining the pairwise correlation between x and other parameters through 2 million simulation cases.At last,the distribution was used as a prior distribution to update the marginal distribution of x with any group of the relevant parameters known.The performance of the dynamic prediction was further validated by the field data of 3 shield tunnel cases.展开更多
Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model tests.However,this phenomenon has seldom been considered in current analytical solutions.This study formulates a tensionles...Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model tests.However,this phenomenon has seldom been considered in current analytical solutions.This study formulates a tensionless Winkler solution that could make allowance for gap formation in soil-pipeline interaction analyses.The solution is validated by comparisons with existing experimental measurements and two recognized analytical solutions.Also,its advantage over an existing Winkler solution is addressed.Further parametric studies reveal that the effects of gap formation on the response of a pipeline rely largely on the tunnel volume loss and the pipeline’s bending stiffness and burial depth.In general,a pipeline’s bending moments and subgrade reaction forces are more susceptible than its deflections to the gap formation.展开更多
基金supported by the National Natural Science Foundation of China(No.52272198 and 52002122)the Project funded by China Postdoctoral Science Foundation(No.2021M690947).
文摘Aqueous Zn-ion batteries(AZIBs)have attracted increasing attention in next-generation energy storage systems due to their high safety and economic.Unfortunately,the side reactions,dendrites and hydrogen evolution effects at the zinc anode interface in aqueous electrolytes seriously hinder the application of aqueous zinc-ion batteries.Here,we report a critical solvation strategy to achieve reversible zinc electrochemistry by introducing a small polar molecule acetonitrile to form a“catcher”to arrest active molecules(bound water molecules).The stable solvation structure of[Zn(H_(2)O)_(6)]^(2+)is capable of maintaining and completely inhibiting free water molecules.When[Zn(H_(2)O)_(6)]^(2+)is partially desolvated in the Helmholtz outer layer,the separated active molecules will be arrested by the“catcher”formed by the strong hydrogen bond N-H bond,ensuring the stable desolvation of Zn^(2+).The Zn||Zn symmetric battery can stably cycle for 2250 h at 1 mAh cm^(-2),Zn||V_(6)O_(13) full battery achieved a capacity retention rate of 99.2%after 10,000 cycles at 10 A g^(-1).This paper proposes a novel critical solvation strategy that paves the route for the construction of high-performance AZIBs.
基金supported by funding from the National Natural Science Foundation of China (Grant Nos.51978303 and 52208367)the Fundamental Research Funds for the Central Universities (Grant No.2042023kfyq03).
文摘The influence of curing temperature on the strength development of cement-stabilized mud has been well documented in terms of strength-increase rate and ultimate strength.However,the strength development model is not mature for the extremely early stages.In addition,there is a lack of studies on quality control methods based on early-stage strength development.This paper presents a strength model for cement-stabilized mud to address these gaps,considering various curing temperatures and early-stage behaviors.In this study,a series of laboratory experiments was conducted on two types of muds treated with Portland blast furnace cement and ordinary Portland cement under four different temperatures.The results indicate that elevated temperatures expedite strength development and lead to higher long-term strength.The proposed model,which combines a three-step conversion process and a hyperbolic model at the reference temperature,enables accurate estimate of the strength development for cement-treated mud with any proportions cured under various temperatures.With this model,a practical early quality control method is introduced for applying cement-stabilized mud in field projects.The back-analysis parameters obtained from a 36-h investigation at temperature of 60C demonstrated a sufficient accuracy in predicting strength levels in practical applications.
基金The National Natural Science Foundation of China under contract Nos 41706191 and 41961144013the Natural Science Foundation of Zhejiang Province under contract No.LY20D060004+2 种基金the National Natural Science Foundation of China under contract Nos 41676111,41876139 and 41906140the Program of Bureau of Science and Technology of Zhoushan Grant under contract No.2019C81031the Basic Public Welfare Research Project of Zhejiang Province under contract No.LGC22B050032.
文摘More than 30 species of benthic Prorocentrum have been identified,some of which produce okadaic acid(OA)and its derivatives,dinophysistoxins(DTXs),which cause diarrhetic shellfish poisoning(DSP).Increasing numbers of benthic Prorocentrum species have been reported in tropical and subtropical waters of China.In contrast,only a few benthic Prorocentrum species have been reported in temperate waters.In this study,morphological descriptions obtained using light microscopy,scanning electron microscopy and molecular characterization of one Prorocentrum clipeus strain isolated from the Yellow Sea are presented.Prorocentrum clipeus cells were nearly circular in shape,with a collar,ridge,and one protrusion.The periflagellar area was wide U-shaped,with two curved projections on platelet 1a.Nine periflagellar platelets of different sizes were observed.The morphology closely fits that of the species isolated from other locations.Phylogenetic analysis based on the molecular sequences of the small subunit(SSU)rDNA,internal transcribed spacer(ITS),and large subunit(LSU)rDNA was performed.A comprehensive metabolomic analysis incorporating target,suspect and non-target screenings was first applied to investigate the intracellular and extracellular metabolite profiles of the current isolate of P.clipeus.According to the results of the target and suspect screenings,179 metabolites or toxins produced by DSP-related algal species,including OA,dinophysistoxin-1(DTX1),dinophysistoxin-2(DTX2)and pectenotoxin-2(PTX2),were not detected.Non-target screening involving feature-based molecular networking(FBMN)provided a global view of major metabolites produced by the P.clipeus DF128 strain and revealed 23 clusters belonging to at least 13 compound classes,with organometallic compounds,lipids and lipid-like molecules,phenylpropanoids and polyketides,and benzenoids as major types.To date,this is the first record of the characterization of P.clipeus in samples from Chinese waters.Our results support the wide distribution of epibenthic Prorocentrum species.
基金the financial support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319 and 52108307)the Natural Science Foundation of Fujian Province,China(Grant No.2022J05127).
文摘Calcium salt is an important contributing factor for calcium-based biomineralization.To study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper.Two series of biomineralization tests in solution and sand column,respectively,were conducted.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) crystals.The experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this study.The difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).
基金supported by the National Science Fund for Distinguished Young Scholars(81725005)the National Natural Science Foundation Regional Innovation and Development Joint Fund(U20A6005)+5 种基金the National Natural Science Foundation of China(82151315 and 62176129)the National Key Research and Development Program(2022YFC2405605)the Jiangsu Provincial Key Research and Development Program(BE2021617 and BE2022160)the Key Project supported by Medical Science and Technology Development Foundation,Jiangsu Commission of Health(ZD2021026)the Jiangsu Funding Program for Excellent Postdoctoral Talent(2023ZB818)the Postdoctoral Research Project of Changzhou Medical Center,Nanjing Medical University(CMCP202305).
文摘Early-onset mental disorders are associated with disrupted neurodevelopmental processes during adolescence.The methylazoxymethanol acetate(MAM)animal model,in which disruption in neurodevelopmental processes is induced,mimics the abnormal neurodevelopment associated with early-onset mental disorders from an etiological perspective.We conducted longitudinal structural magnetic resonance imaging(MRI)scans during childhood,adolescence,and adulthood in MAM rats to identify specific brain regions and critical windows for intervention.Then,the effect of repetitive transcranial magnetic stimulation(rTMS)intervention on the target brain region during the critical window was investigated.In addition,the efficacy of this intervention paradigm was tested in a group of adolescent patients with early-onset mental disorders(diagnosed with major depressive disorder or bipolar disorder)to evaluate its clinical translational potential.The results demonstrated that,compared to the control group,the MAM rats exhibited significantly lower striatal volume from childhood to adulthood(all P<0.001).In contrast,the volume of the hippocampus did not show significant differences during childhood(P>0.05)but was significantly lower than the control group from adolescence to adulthood(both P<0.001).Subsequently,rTMS was applied to the occipital cortex,which is anatomically connected to the hippocampus,in the MAM models during adolescence.The MAM-rTMS group showed a significant increase in hippocampal volume compared to the MAM-sham group(P<0.01),while the volume of the striatum remained unchanged(P>0.05).In the clinical trial,adolescents with early-onset mental disorders showed a significant increase in hippocampal volume after rTMS treatment compared to baseline(P<0.01),and these volumetric changes were associated with improvement in depressive symptoms(r=−0.524,P=0.018).These findings highlight the potential of targeting aberrant hippocampal development during adolescence as a viable intervention for earlyonset mental disorders with neurodevelopmental etiology as well as the promise of rTMS as a therapeutic approach for mitigating aberrant neurodevelopmental processes and alleviating clinical symptoms.
基金supported by the National Natural Science Foundation of China(22109163 and 52002122)China Postdoctoral Science Foundation(2021M690947).
文摘水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵根离子插层机制所形成的N–H···O强键合作用来稳定Mo–MnO_(2)的2×2隧道结构,并且有效抑制了Mn^(3+)溶解,在质子插入/脱出过程中不会引起晶格的畸变,进一步提高了其循环稳定性.获得的Mo–MnO_(2)正极在100 mA g^(−1)时表现出265.2 mA h g^(−1)的高比容量和364.3 W h kg^(−1)的能量密度.在2.0 A g^(−1)下1000次循环后,容量保持率达95.2%.这项工作有助于深入了解非金属阳离子在电极主体材料间的键合作用,为设计具有高能量密度和长期循环能力的水系锌离子电池提供了新思路.
基金Natural Science Foundation of Jiangsu Province,China,Grant/Award Number:BK20220794。
文摘In this paper,we develop an exhaustive numerical simulator for the dynamic visualization and behavior prediction of the tether-net system during the whole space debris capture phases,including spread,contact,and close.First of all,to perform its geometrically nonlinear deformation,discrete different geometry theory is applied to model the mechanical response of a flexible net.Based on the discretization of the whole structure into multiple vertexes and lines,the internal force and associated Hession are derived in a closed form to solve a series of nonlinear dynamic equations of motion.The spread and deployment of a packaged net can be realized using this well-established net solver.Next,a multidimensional incremental potential formulation is selected to achieve the intersection-free boundary nonlinear contact and collision between the deformable net and rigid debris.Finally,for the closing mechanism analysis,a log-like barrier functional is derived to achieve the nondeviation condition between the ring–rod linkage system.The C2 continuous log barrier functionals constructed for both the contact model and the linkage system are smooth and differentiable,and,therefore,the nonlinear net capture dynamic system can be efficiently solved through a fully implicit time integrator.Overall,as a demonstration,the whole capture process of a defunct satellite using a hexagon net is simulated through our well-established numerical framework.We believe that our comprehensive numerical methods could provide new insight into the optimal design of active debris removal systems and promote further development of the online control of tether tugging systems.
文摘A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrothermal and microwave hydrothermal method.The morphological studies revealed that the ZnFe-LDO/Co_(3)O_(4) composites exhibited a flower-like structure comprising Co_(3)O_(4) nanowires and ZnFe-LDO nanosheets.Further,when the mass ratio of Co(NO_(3))_(2)·6H_(2)O/LDH was 1:1.8 and the calcination temperature was 550℃,the ZnFe-LDO/Co_(3)O_(4) composite exhibited 93.3%degradation efficiency for methylene blue(MB)at the applied voltage of 1.0 V under visible light after 3 h.Furthermore,the Mott-Schottky model experiments showed that the formation of a p-n heterojunction between ZnFe-LDO and Co_(3)O_(4) could effectively inhibit the recombination of electrons and holes in the photoelectrocatalytic process.Meanwhile,free radical scavenging experiments showed that the active radicals of⋅OH played an important role in the degradation of MB.Therefore,the photoelectrocatalytic effect of ZnFe-LDO/Co_(3)O_(4) provides a simple and effective strategy for the removal of organic pollutants.
文摘A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete(PC)box-girder bridge.The change of hydration heat temperature consists of four periods:temperature rising period,constant temperature period,rapid temperature fall period and stow temperature fall period.The peak value of hydration heat temperature increases with the increasing casting temperature of concrete;the relation between them is approximately linear.According to field tests,the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder.Furthermore,the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring.Such results show that the prevailing Chinese Code(2004)is insufficient since it does not take into account the temperature gradient of the bottom slab.Finally,some preventive measures against temperature cracks were proposed based on related studies.The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.
文摘Based on high specific surface area,high porosity of metal-organic frameworks(MOFs)and excellent vis-ible light response of CdS,the CdS/Cd-MOF nanocomposites were constructed by in-situ sulfurization to form CdS using Cd-MOF as precursor and the CdS loading was controlled by the dose of thioac-etamide.Under the irradiation of simulated sunlight,the degradation rate of methylene blue(MB)by 10mg MOF/CdS-6(mass ratio of MOF to thioacetamide is 6:1)was 91.9%in 100min,which was higher than that of pure Cd-MOF(62.3%)and pure CdS(67.5%).This is attributed to the larger specific surface area of the composite catalysts,which provides more active sites.Meanwhile,the loading of CdS obvi-ously broadens the light response range of Cd-MOF and improves the utilization of visible light.The Mott-Schottky model experiment shows that the formed type-Ⅱheterojunction between Cd-MOF and CdS can effectively inhibit the recombination of photogenerated electrons and holes.Meanwhile,the photocurrent intensity of MOF/CdS-6 is 8 times and 2.5 times of that of pure Cd-MOF and CdS.In addi-tion,MOF/CdS-6 showed good photocatalytic performance after five cycles,showing excellent stability and reusability.
文摘This paper deals with the floating resistance of super large caisson by numerical simulation,and the influence of air resistance on the caisson,which is often ignored by previous researchers,is considered.The floating caisson of Taizhou Highway Bridge’s middle tower pier is investigated,and the software package FLUENT is used to simulate the floating process of largescale rounded rectangular steel caisson.This simulation adopts the volume of fluid(VOF)model with water-air two-phase flow,which can take both the hydraulic resistance and air resistance into account.Subsequently,the analyses on hydraulic resistance and air resistance under different working conditions,such as different flow velocities and different draughts of water are performed,and the results are compared with those calculated by related empirical formula.The comparison shows that the air resistance takes up notable portion in the total resistance on the floating caisson,and the effect of air resistance on the safety of caisson should be paid sufficient attention to rather than be ignored.
基金supported by the Hubei Communications Department,P.R.China(Grant No.[2005]361).
文摘Concrete box culverts are widely used in expressways in mountain areas.Many problems frequently take place due to improperly estimated vertical earth pressures on culverts.The prevailing Chinese General Code for Design of Highway Bridges and Culverts(CGCDHBC)stipulates the computation of the design load on culverts primarily based on the linear earth pressure theory,which cannot accurately describe the variation of the vertical load on culverts in trenches.In this paper,a full-scale experiment and numerical simulation were conducted to evaluate the variation of vertical earth pressures on culvert and soil arching in backfill.The variations of foundation pressure and settlement were also analyzed.The result revealed that the soil arch forms when the backfill on the culvert reaches a certain height.The soil arching effect reduces the stress concentration on the crown of the culvert but it is unstable.The vertical earth pressure on top of the culvert is significantly different from that recommended by the CGCDHBC.
基金This work was supported by the National Grand Program on Key Infectious Disease(No.2018ZX10103002-001-007)the Biosafety Special Program(No.19SWAQ 13).
文摘Background:The coronavirus disease 2019(COVID-19)is a highly infectious respiratory disease.There is no recommended antiviral treatment approved for COVID-19 in Sierra Leone,and supportive care and protection of vital organ function are performed for the patients.This study summarized the clinical characteristics,drug treatments,and risk factors for the severity and prognosis of COVID-19 in Sierra Leone to provide evidence for the treatment of COVID-19.Methods:Data of 180 adult COVID-19 patients from the 34th Military Hospital in Freetown Sierra Leone between March 31,2020 and August 11,2020 were retrospectively collected.Patients with severe and critically ill are classified in the severe group,while patients that presented asymptomatic,mild,and moderate disease were grouped in the non-severe group.The clinical and laboratory information was retrospectively collected to assess the risk factors and treatment strategies for severe COVID-19.Demographic information,travel history,clinical symptoms and signs,laboratory detection results,chest examination findings,therapeutics,and clinical outcomes were collected from each case file.Multivariate logistic analysis was adopted to identify the risk factors for deaths.Additionally,the clinical efficacy of dexamethasone treatment was investigated.Results:Seventy-six(42.22%)cases were confirmed with severe COVID-19,while 104 patients(57.78%)were divided into the non-severe group.Fever(56.67%,102/180)and cough(50.00%,90/180)were the common symptoms of COVID-19.The death rate was 18.89%(34/180),and severe pneumonia(44.12%,15/34)and septic shock(23.53%,8/34)represented the leading reasons for deaths.The older age population,a combination of hypertension and diabetes,the presence of pneumonia,and high levels of inflammatory markers were significantly associated with severity of COVID-19 development(P<0.05 for all).Altered level of consciousness[odds ratio(OR)=56.574,95%confidence interval(CI)5.645–566.940,P=0.001],high levels of neutrophils(OR=1.341,95%CI 1.109–1.621,P=0.002)and C-reactive protein(CRP)(OR=1.014,95%CI 1.003–1.025,P=0.016)might be indicators for COVID-19 deaths.Dexamethasone treatment could reduce mortality[30.36%(17/56)vs.50.00%(10/20)]among severe COVID-19 cases,but the results were not statistically significant(P>0.05).Conclusions:The development and prognosis of COVID-19 may be significantly correlated with consciousness status,and the levels of neutrophils and CRP.
基金support provided by the National Natural Science Foundation of China(Grant Nos.52078236 and 52122806)Guangzhou Metro Group Co.,Ltd(JT204-100111-23001)Chongqing Urban Investment Infrastructure Construction Co(Grant No.CQCT-JS-SC-GC-2022-0081).
文摘The probability analysis of ground deformation is becoming a trend to estimate and control the risk brought by shield tunnelling.The gap parameter is regarded as an effective tool to estimate the ground loss of tunnelling in soft soil.More specifically,x,which is a gap parameter component defined as the over(or insufficient)excavation due to the change in the posture of the shield machine,may contribute more to the uncertainty of the ground loss.However,the existing uncertainty characterization methods for x have several limitations and cannot explain the uncertain correlations between the relevant parameters.Along these lines,to better characterize the uncertainty of x,the multivariate probability distribution was developed in this work and a dynamic prediction was proposed for it.To attain this goal,1523 rings of the field data coming from the shield tunnel between Longqing Road and Baiyun Road in Kunming Metro Line 5 were utilized and 44 parameters including the construction,stratigraphic,and posture parameters were collected to form the database.According to the variance filter method,the mutual information method,and the value of the correlation coefficients,the original 44 parameters were reduced to 10 main parameters,which were unit weight,the stoke of the jacks(A,B,C,and D groups),the pressure of the pushing jacks(A,C groups),the chamber pressure,the rotation speed,and the total force.The multivariate probability distribution was constructed based on the Johnson system of distributions.Moreover,the distribution was satisfactorily verified in explaining the pairwise correlation between x and other parameters through 2 million simulation cases.At last,the distribution was used as a prior distribution to update the marginal distribution of x with any group of the relevant parameters known.The performance of the dynamic prediction was further validated by the field data of 3 shield tunnel cases.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52174101 and 52208380)the Department of Science and Technology of Guangdong Province,China(Grant No.2021ZT09G087)+4 种基金the Guangdong Basic and Applied Basic Research Foundation,China(Grant Nos.2023A1515030243,2023A1515011634)Zhuhai Basic and Applied Basic Research Foundation,China(Grant No.ZH22017003210005PWC)the open fund project of Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province,China(Grant No.ZUCC-UST-22-03)General Research and Development Projects of Guangdong Provincial Communications Group Co.,Ltd.,China(Grant No.JT2022YB25)Highway Projects of Guangdong Provincial Development and Reform Commission,China(Grant No.2108-441400-04-01-637272).
文摘Soil-pipeline separation due to tunnelling has been certainly substantiated in previous model tests.However,this phenomenon has seldom been considered in current analytical solutions.This study formulates a tensionless Winkler solution that could make allowance for gap formation in soil-pipeline interaction analyses.The solution is validated by comparisons with existing experimental measurements and two recognized analytical solutions.Also,its advantage over an existing Winkler solution is addressed.Further parametric studies reveal that the effects of gap formation on the response of a pipeline rely largely on the tunnel volume loss and the pipeline’s bending stiffness and burial depth.In general,a pipeline’s bending moments and subgrade reaction forces are more susceptible than its deflections to the gap formation.
